Dish-type satellite antennas are well known, and are increasingly coming into use, for example, for reception of direct television broadcast signals from satellites. A typical satellite antenna intended for residential use in receiving direct broadcast television transmissions is schematically illustrated in FIG. 1. As shown in FIG. 1, reference numeral 10 generally indicates the satellite antenna. The satellite antenna 10 includes a support post 12 which extends vertically upwards from a mounting base or bracket (not shown). An antenna assembly 14 is mounted on the support post 12 by means of an adjustable mounting mechanism 16. The antenna assembly 14 includes a signal reflecting dish antenna 18 and a low noise block 20 mounted on a supporting arm 22 at a fixed position in relation to the dish 18.
The dish 18, in a typical home-use embodiment, is about 18 inches in diameter and is curved so as to convergingly reflect the satellite broadcast signal toward the low noise block 20.
As is well known to those skilled in the art, the low noise block 20 includes conventional circuitry (not shown in FIG. 1) including a high-gain, low noise amplifier which receives and amplifies the satellite broadcast signal reflected thereto by the dish 18. The amplified signal is output from the low noise block 20 via a coaxial cable 24. Because the antenna 10 is exposed to the elements, it is highly desirable that the low noise block 20 have an external housing 26 that is durable and sealed so as to be weather-resistant in order to protect the electronic components contained therein.
In a typical installation, the satellite 10 is installed on a rooftop, or elsewhere outside of a residence, and the coaxial cable 24 extends into the residence for connection to a set-top "box" module (not shown) connected as a signal source to a television set (not shown).
In order to provide satisfactory signal reception to the television set, it is necessary to install the satellite antenna 10 so that a signal reception axis of the dish 18 is oriented with reasonable accuracy toward the satellite from which the direct broadcast television signal is to be received. For this purpose, the mounting mechanism 16 includes conventional arrangements, shown only schematically in the drawing, which permit the antenna assembly 14 to be rotated horizontally (as indicated by arrows 28) and vertically (as indicated by arrows 30) with respect to the support post 12. Scale markings 32, for indicating the vertical rotational elevation of the antenna assembly 14, are also typically provided.
For optimum adjustment of the orientation of the dish 18 relative to the satellite, it is known to provide a circuit in the aforementioned set-top unit for detecting the strength (i.e., the amplitude) of the received satellite signal and for controlling the television set so that a bar graph or similar display indicative of the signal strength is provided on the television screen. The amplitude measurement and display function may be actuated, for example, by selection of a menu item, using a remote control device provided to control the set-top unit and with reference to a menu displayed on the television screen. Essentially, the orientation of the dish 18 is adjusted on a trial-and-error basis until a maximum received signal amplitude is indicated on the television screen display.
The above-described technique of displaying an indication of the received signal amplitude on the television screen suffers from a number of disadvantages. As noted before, the satellite antenna 10 is usually installed outside of the building, and perhaps on the roof. Thus, the location at which the orientation adjustments are to be made (i.e., at the satellite antenna 10) is physically remote from the television screen on which the amplitude indication is displayed. If an individual attempts to adjust the orientation of the antenna assembly 14 without assistance, the orientation adjustment may require numerous trips by the individual back and forth between the satellite antenna 10 and the vicinity of the television screen for the purpose of alternately adjusting the antenna's orientation and determining the resulting effect on received signal amplitude by referring to the television screen display. Such a procedure may be particularly arduous if the satellite antenna 10 is installed on the roof of the building.
Even if two or more people participate in the task of adjusting the antenna orientation, there may be significant inconvenience, including difficulty in communicating instructions such as "up", "down", "left", "right", etc. from a person who is in a position to view the television screen to another person who is in a position to physically manipulate the satellite antenna 10 to adjust the orientation of the antenna assembly 14.
A further disadvantage is that the known technique as described above does not allow pre-positioning of the satellite antenna 10. In other words, the above-described technique cannot be used unless both a working television receiver and set-top unit are available and connected to the satellite antenna 10.